Means for controlling an engine-driven gas compressor



July 1, 1958 G- B. BOYCE 23 117321 MEANS FOR CONTROLLING AN ENGINE-DRIVEN GAS COMPRESSOR Filed 001;. 25, 1954 3 Sheets-Sheet 1 y 1958 G. B. BOYCE 2,841,321

MEANS FOR CONTROLLING AN ENGINE-DRIVEN GAS COMPRESSOR Filed 001:. 25, 1954 3 SheetsSheet 2 G. B. BOYCE July 1, 1958 MEANS FOR CON'IKOLLING AN ENGINE-DRIVEN GAS COMPRESSOR 3 Sheets-Sheet 3 Filed Oct. 25, 1954 EN 7 S 4 United States Patent Office My 2,841,321 MEANS FOR CONTROLLING AN ENGINE-DRIVEN GAS COMPRESSOR Guy Baron Boyce, Shenstone, England, assignor to The Hydrovane Compressor Company Limited, Walsall, England Appiication ()ctober 25, 1954, Serial No. 464,463 Claims priority, application Great Britain November 4, 1953 4 Claims. (Cl. 230-9) This invention relates to means for controlling the action of an engine-driven air or other gas compressor, the engine being of the internal combustion type, and the compressor being of the type comprising a rotor mounted in a working chamber and provided with slidable radial vanes, the sealing of the vanes being effected by oil which is supplied to the working chamber under pressure from a separator which receives oil-laden air from the compressor.

The object of the inventionis to provide in a convenient form an engine (or engine and compressor) control means responsive to the pressure of oil received fr'or'n the separator.

A control means in accordance with the invention includes a spring-loaded throttle adapted to control the fiow of oil from the separator to an oil accumulating chamber, and an engine controlling mechanism responsive to the pressure of the oil received from the said chamber.

The invention also comprises the combination with the means specified in the previous paragraph of a valve operable by pressure of the oil received from the said chamber for controlling the admission of air to the compressor.

A convenient embodiment of the invention will be described, by way of example, with particular reference to the accompanying drawings in which:

Figure 1 is a diagrammatic View showing the interrelationship and mode of interconnection of the parts, some of which are illustrated in detail in the other figures.

Figure 2 is a sectional view through the body part containing the throttle and fluid operated valve controlling the air admission aperture of the compressor.

Figure 3 is a sectional view of the mechanism for varying the setting of the governor.

Figure 4 is a sectional view of mechanism whereby air pressure can be utilised for actuating the mechanism seen in Figure 3, and,

Figure 5 is a device for permitting the control to be effected directly upon the engine throttle or fuel supply instead of upon the engine governor.

Figure 6 is a diagram illustrating the manner in which the device shown in Figure 5 is connected to the associated parts.

In Figure l, 6 represents the internal combustion engine which drives a compressor 7 of known kind, having an eccentrically mounted rotor with slidable radial vanes in a cylindrical working chamber, the sealing of the vanes being eflfected by oil which is supplied to the working chamber under pressure from a separator 8. The admission of air to the compressor 7 is by way of a conduit 9 from an air inlet 10 controlled by a valve 11. The separator 8 separates the admixture of air and oil delivered by the compressor 7 and delivers the air under pressure to the pipe 12 which is connected to the associated air distributing system. The compressor, separator and other parts above described may be similar to those illustrated in Figures 3, 3a and 3b of U. S. Patent No. 2,722,395 in which the separator has the form of an oil reservoir into which oil-laden air from the compressor is discharged. The oil from the separator, which is at the same pressure as the air, is connected by means of the pipe 13 to a port 14 in a body part 15 having a bore 16 (Figure 2) containing a cylindrical and spring loaded throttle 17. The throttle 17 controls the flow of oil to an annular chamber herein referred to as the oil accumulating chamber 18, formed in the bore 16. The oil accumulating chamber 18 is connected by a passage 19 and pipe 29 to a mechanism 21 to be actuated by pressure of the oil and to he referred to hereinafter. Another passage 22 in the body part 15 leads from a circumferential groove 23 in the bore 16 to the compressor 7, the connection between this passage and the compressor being indicated by 22a in Figure 1. In the part of the throttle 17 which forms the inner peripheral boundary of the oil-accumulating chamber 18 is formed a shallow groove 24 by which oil can seep from the said chamber to the groove 23 and thence to the compressor.

The throttle 17 is so formed that a small variation of the oil pressure acting on it is accompanied by a relatively large variation of the pressure in the oil-accumulating chamber 18, the spring 25 determining at what pressure in the separator 7 oil is admitted to the oil accumulating chamber.

The mechanism 21 to be actuated by the oil pressure serves to vary the setting of the engine governor 26, which latter controls the throttle 27 in the air-intake manifold of the engine, or the supply of liquid fuel. In one example the mechanism 21 (seen in Figure 3) comprises a hollow body part 28 having an inlet port 29 to which the pipe 20 is connected. The body part 28 is also provided with a restricted bleed orifice 28 leading to atmosphere via port 28 and in which is contained a compressible spring loaded elastic metal bellows 30. One end of the bellows Si? is fixed, and the closed movable end 3% acts on a slidable rod 31 which is disposed within the bellows and is connected to a lever 32 pivotally mounted on the said body part, the lever 32 being connected by a link 33 to the governor 26. The pivot 34 of the lever 32 is carried on a spring-loaded stem 35 in the body part, so that when the governor is moved to one of its limit positions any additional movement of the bellows 30 is accommodated by displacement of the pivot axis.

It will be understood that in an apparatus which includes an engine, a compressor, and an oil separator as above mentioned, the ch in the separator 8 is subject to the pressure of the air discharged from the compressor 7 to the associated air distributing system (the term air being herein intended to include any gas). This pressure is at its maximum when no air is being drawn from the system, and at other times it varies with the rate of demand for air.

In the arrangement above described oil from the separator 8 is returned to the compressor 7 through the throttle 17, and the pressure of the oil retained in the oil-accumulating chamber 18 varies with the demand for air. When the demand is zero, the oil pressure acting on the bellows 3% causes the governor 26 to reduce the speed of the engine 6 to the idling speed. It may be, however, that this alone is insufficient to reduce to the desired relatively low amount the pressure to which the air is compressed by the compressor 7.

To meet this requirement the accumulating chamber 13 is in communication, through a passage 36 with the region 37 in a bore parallel with the bore 16. In the said bore is a fixed bush 38 in which is slidable the hollow stem 39 of an air-inflow controlling member. This member has a head 39a upon which the oil pressure acts and is spring loaded in opposition to the oil pressure by a spring 4-0 interposed between a foot 41 on the said member and the fixed bush 38.

In the hollow stem 39 is freely slidable the stem 11a of the va1ve 11 which controls the adrnis sioniof through the inlet to the passage .42,-.whichis con-.

" nected by the pipe 9 to the, compressor. 'Movement of the head 39a to the right as viewed in'the drawing, due

to an incre'ase inoil-pressurefin theioil accumulating chambergcloses or' partially closes .theizvalve 11 upon its seatydue to thei'a'butment of the head ,39a,with a' shoulder onthe valve 11. Consequently'when an excess air pressure persists: at idling speed the load on the compressor is furthe'rireduced by restriction or interruption of the air supply tb'the'compr'es'sor; The left hand .end of the :bore.16- is in communication through passage'43 and'an axial bore 44 in the valve ll and thepressure were-again to rise infth'e conip'ressor' .thus causing. the. inlet control valvell to ,close,,thef

i withthe engine throttle 'or;fuel controllin'gllever. 'The link 33 is formed in two parts, one partbeing connected with atmosphere to prevent hunting of the throttle 17 '1 when the compressor isrin action. When the compressor is at rest and the associated system is under pressure, loss of this pressure by 'leakage of. oil past the throttle -7 and through passage 43 and bore 44 is prevented by a non-return valve 45. v a

Q Althoughin Figure 1 the compressor'l, separator 8, and body part are shown for simplicity as separate units connected by'pipes, in practice they are all contained within a common casing. a In th e foreg'oing arrangement the bellows 30 is actuated directly by pressure of the oil. But insome conditions-this is undesirable, for in the event of fracture of the pipe 29 leading to the'bellows, inconvenient loss oi oil would result. To obviate this compressed'air may be used-for actuating the bellows '30, it being of less consequence tolose air than oil in the event of fracture of the pipe connected to the bellows. In an alternative arrangement, in conjunction with the above described bellows-actuating means the device illustrated in Figure 4 therefore,.may be employed.

The passage 19 may be connected by the pipe to the inlet 46 of a cylinder 47 having an outlet 48 for compressed air, which is connected to ,the inlet 29 of the device seen in Figure 3. In the cylinder 47. is a 'spring loaded piston 49 which acts upona slidable throttle 50, which serves to open a spring-loaded air valve 751, controlling the admission of compressed air from an inlet 52.- The throttle 50 consists of a tapered plug slidable in a'cylindricalbore; so as to :form a variable orifice for admitting the compressed air to the underside of the piston 49 and thence to the outlet 48 The oil entering the cylinder above the piston from the inlet '46 passes through a restricted orifice in a spring loaded 'valve 53. lf'pressure is reduced at the inlet 46 oil can flow back through the inlet relatively quickly by lifting this valve on its seat 1 V A 'variable oilpressure acting on the piston 49 consequently results in a correspondingly varying air pressure for'actuating the bellows 30. Thus, downward movepressed air from the inlet 52 to the cylinder after the throttle has been moved downwards to a predetermined -extent. Upon the piston 49 being subsequently moved upwards, due to decrease of the oil pressure acting thereon, the throttle 50 moves towards its closed position so that the upward movement of the piston causes the air pressure in the cylinder 47, and acting on the bellows, to be reduced due to the escape of air through bleed orifice 28', the valve51 closing if the upward movement of the piston is suflicient.

'In Figures 5 and 6 is illustrated a compensating'device whereby the lever 32 (Figure 3) may be connected fto the throttle 27 or fuel controlling device of the engine 6 without using a governor. if the lever 32 were connected directly to the throttle It willbe understood that, a

to a housing 54jcontaining a diaphragm 55, and the other part being connected to a plunger 56 connected 'to the.

diaphragm 55 and slidableina cylindrical portion'of the housing54. The interior of the housing is'in communication through a port 57-'and a passageway. with.

the air intake to' the compressor 7 onthe down-stream side of the valve 11. 'The arrangement is such that a reducedpressure ,inl'theair .intake will cause a relative axial movementofj't'he two' parts ofthelink -33 against the action of a spring'58fto shorten the etfectiiieileng thj' i 1. Means for controlling the action or an engine-driven air or other gas compressor of the kind inwhich a rotor .a passageway connecting said accumulating. chamber. and a said actuating means for conducting oil under pressure from ,the accumulatingchamber to the valve actuating .ment-of the piston 49 is accom'paniedby compression 01' fuel controlling device 27 without some form of "compensation, then when the engine'speedwere reduced mounted in a working'chamberis providedwithlradial vaneswhich are sealablelbyfoil supplied under; pressure g to the working chamber from a separatorreceivin'g oil-. laden air from the compressor, comprising combination an oilaccumulating chamber, a passage-for con dilcting'oil ri ss s Ys r snm eaccumulating chamber, a spring-loaded tlirettle arranged in said passage f orcontrolling oil flow to the accumulat-' ing chamber, aniengine controlling mechanism haying an actuating member responsive ,to fluid 'pressure and means interconnecting said accumulatingchambr and said actuating member for subjecting the actuatingjmemher to a fluidpressure which varies with' the oilipressure in the accumulating chamber.v V V 2. Means according to claim 1' and having incombination therewith afvalve for controlling the admission 7 of air to the "compressor, actuating means through the medium of whichthe valve is operable by oil pressure, and

means.

3. Means according to clainr "1 and haiving in com-I bination therewitha cylinder, a spring-loaded piston slidable in the cylinder, a=passa'geway interconnecting the accumulating chamber. and ;the cylinder to conduct oil underpressure from; the accumulating chamber to the cylinder atone side, of theipistonfor moving the member of'the engine-controlling mechanism, and a valve operable by the piston :,for controlling the flow of the air under pressure to the part of the cylinder communivcatinglwith the secondlpassageway so that the air presi Sure acting onthe actuating member varies with thepressurejof the 'oil in the accumulating chamber.- 7 4. Means according to claim 1 and having in combinationf vs'rith itheengine-controlling.mechanism; a twoa.

part link through which, the controllingaction of the said mechanism: is eifected,'jand acompensating device interconnecting the link'parts,,the said'device' havingcom- -ponents;relatively movable"v in. response to .air "for varyingthe efiectiv'e length of the link. i

V V References Citedin the file of patent T g QUNITED 'STATES PATENTS 2,135,248

pressure,

Nov. 1, 1938 Paget Mar. 27, 1951 

